<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
        "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
    <title>并集选择器</title>
    <style type="text/css">
        h1,h2,h3,h4,h5,p{  /*并集选择器*/
        color:purple;
        font-size:15px;
        }
     h2.special,.special,#one{   /*集体声明*/
        text-decoration:underline; /*下划线*/
        }

    </style>
</head>
<body>
    <h1>实例文字</h1>
    <h2 class="special">示例文字</h2>
    <h3>示例文字</h3>
    <h4>示例文字</h4>
    <h5>示例文字</h5>
    <p>示例文字</p>
    <p class="special">示例文字</p>
    <p id="one">示例文字</p>
</body>
</html>